@comlys I noticed you requested access to the file yesterday - have you been able to access and review the packaged application?
Have you been able to gather any more intel on the matter by any chance?
I created a completely new material for the mirrors (Reflection 0, Metalness 1) to ensure it’s not material related, but I received the same reflection issue.
It therefore seems to be render-setting related, from what I can tell.